1)
1.6x - (x - 2.8) = (0.2x + 1.5) - 0.7
1.6x - x + 2.8 = (0.2x + 1.5) - 0.7 distributed the negative sign on left
0.6x + 2.8 = 0.2x + 0.8 combined like terms on the left and right
0.4x + 2.8 = 0.8 subtracted 0.2x from both sides
0.4x = 3.6 added 2.8 to both sides
x = 9 divided both sides by 0.4
2)
4(y - 0.8) = 3.8y - 5.8
4y - 3.2 = 3.8y - 5.8 distributed 4 on the left side
0.2y - 3.2 = -5.8 subtracted 3.8y from both sides
0.2y = 9.0 added 3.2 to both sides
y = 45 divided both sides by 0.2
3)
2a = 9b ⇒ 2:9
4)
a + b = 3b ⇒ a = 2b ⇒ 1:2
Answers: 9, 45, 2:9. 1:2
